Artificial testing soil and method of testing

ABSTRACT

An artificial test soil comprises particulate, hair, and fiber components, wherein said particulate component consists of mineral, food, and plant materials, so chosen and proportioned as to correlate to a typical soil found in the home. The test soil may be used to test cleaning products by application of a known amount thereof to a surface, cleaning of said surface, and determination of the amount of said soil removed from said surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/172,637, filed on Jun. 14, 2002, which claims the benefit ofU.S. Provisional Application Ser. No. 60/298,645, filed Jun. 15, 2001.

BACKGROUND OF THE INVENTION

This invention relates to a synthetic soil composition for use intesting cleaning implements with or without separate or combinedcleaning compositions, and a method of conducting such testing. Dustingdevices and cleaning cloths need to pick up dust and dirt commonly foundaround the home. There is a need to be able to consistently test thesecloths and cleaning devices to allow comparisons that will accuratelycorrelate to how these cloths and devices will perform in the “realworld”. Since there can be a wide variation of dust and dirt found in atypical home environment, and even the same home over differing periodsof time, it is not considered feasible to collect soil, from anindividual home, or even a series of homes, and use this as areproducible testing material.

In the past, various artificial soils and test methods have beenattempted for this purpose, but none have been found to correlate towhat could be considered a typical home environment. For example, U.S.Pat. No. 5,928,948, of Malchesky, teaches a method for assessment andevaluation of a cleaning process comprising the steps of contaminating aporous material with a known soil, subjecting the porous material andthe soil to the cleaning process to be assessed and evaluated, andevaluating the cleaning process on the basis of the soil not removed bythe cleaning process. The test procedure of the present invention doesnot involve contamination of a porous material, and the soil employed bythe patentee does not correspond to the soil of the present invention,but is more closely related to organic contamination more likely foundin a medical, dental, surgical, or veterinary facility than in a typicalhome environment.

In U.S. Pat. No. 4,867,614, Freed teaches a composite mixture comprisingsoil and from about 0.1 to 5 percent of additive discrete fibermaterials. The soil comprises natural soil selected from a groupincluding sand, clay, and mixtures thereof, and the fiber materials arediscrete fibers selected from man-made fiber forming substances andfiberglass, present to improve the punching resistance, total angle ofinternal friction, average total cohesion, and average initial tangentmodulus of the soil. The present test soil is not reinforced so as toprovide improved engineering properties as is that of the patentee. Thecomposite soil mixture of the patent is provided to have improved loadbearing capability and related engineering properties to benefitfoundations and column supports, while the present invention is designedto correspond to a typical form of dirt or soil to be found in a typicalhome setting and the two soils have little in common.

U.S. Pat. Nos. 6,302,936 and 6,419,722, of Adam, claims an artificialsoil composition comprising a homogenous mixture of a blending base,cellulose, bio-solids, calcium in any form burned crop waste orvegetation, and ammonium sulfate. Also claimed is a process for makingthe artificial soil. The purpose of the artificial soil proposed by Adamis for crop growth, rather than for a test material for evaluation of acleaning composition or method, and the artificial soil of Adamcomprises a very different mixture than that of the present invention.

In U.S. Pat. No. 5,312,661, Suzuki et al. teaches an artificial soilcomprising porous granules consisting essentially of a plurality ofthermoplastic resin foamed particles. The present invention does notinclude the presence of thermoplastic resin foamed particles, which arepresent in the patented composition to provide improved air permeabilityand drainage, which properties would not be of value in the purpose ofthe present invention.

A synthetic test soil is taught by Pfeifer, in U.S. Pat. No. 6,107,097,relating to test stains comprising isolated fibrin and/or fibrinprecursors and blood plasma proteins. The present invention does notcomprise fibrins or fibrin precursors, and does not relate to thetesting of cleaning procedures for medical or surgical instruments.

In addition to the above, the following patents further show the stateof the art: U.S. Pat. No. 5,137,460, of Middleton; U.S. Pat. No.5,397,392, of Derr; U.S. Pat. No. 5,502,998, of Miller et al.; U.S. Pat.No. 5,583,165, of Kviesitis; Franklin et al. U.S. Pat. No. 4,792,363;Requejo et al., U.S. Pat. No. 5,090,975; Ahlberg et al., U.S. Pat. No.5,461,749; Ditze et al., U.S. Pat. No. 5,877,138; Willman et al., U.S.Patent Application Publication No. US 2002/0050016; Lemay, U.S. Pat. No.6,846,858; and Japanese Patent 7-35680, of Noritake et al. However, noneof the prior art shows a soil which is typical of the type of soil ordirt to be found in a normal home or non-medical work environment, or amethod for testing a cleaning composition, implement, or proceduresuitable for use in such a normal home environment. It is also to benoted that the present invention is intended to be used in a hardsurface cleaning environment, as opposed to a carpeted environment.Thus, the test soil of the present invention is intended to correlate toa soil or dust normally found on hard surface areas of the home, not ina carpeted area, and accordingly, the artificial test soil of theinvention is not anticipated to be similar to soil removed fromcarpeting by vacuum cleaning.

Furthermore, these prior soil compositions relate generally tocompositions which are normally found on a floor surface of a home, suchas a carpeted, hardwood, tile, or other flooring surface. Thus, thesetest soils do not accurately reflect the types of fibers andparticulates which form dust compositions that, in addition to beingfound on flooring surfaces, are also located on other surfaces elevatedabove the flooring surface, such as on tables, chairs, and window sills,among others. The reason for this is that the dust composition is formedof lighter components than typical soil compositions that enable thedust compositions to be carried in vertical as well as horizontaldirections by air currents in the home. Thus, because of this differencein composition from normal household soils, it is desirable to developan artificial or simulated dust composition that can be utilized to testvarious cleaning devices on their ability to pick up and removehousehold dust compositions, which are necessarily significantlydifferent from soil compositions found virtually exclusively on flooringsurfaces.

SUMMARY OF THE INVENTION

The synthetic testing soil of, the present invention comprises: fromabout 40% to 80% of at least one particulate component, and from about20% to 60% of at least one hair component, wherein the particle sizedistribution of the particulate component composition is from 1% to 10%less than 75 microns; from 10% to 30% between 75 microns and 300microns; and from 60% to 85% greater than 300 microns. In addition, anadditional fiber component may optionally be present, in an amount up toabout 40%. It is preferred to have the fiber component present in anamount of from about 10% to 30% by weight and most preferably from about20% to 30% by weight. The component percentages are weight percentagesbased upon the total weight of the testing soil.

The testing method comprises applying a pre-measured quantity of a testsoil to a specific size test surface by first, randomly but evenlydistributing a particulate component of a test soil to the surface, andsecond, randomly but evenly distributing a hair component of a test soilto the surface by separating the hair fibers from each other into atleast ten divisions of fibers and distributing these divisions of fibersto the surface; applying the cleaning product to the test surface toremove the test soil; and measuring the amount of test soil that hasbeen removed by the cleaning product from the surface to obtain therelative efficiency of the cleaning product.

It was unexpectedly found that one synthetic soil closely mimics thesoils from seven geographically diverse areas of the country, and thatdry soil samples obtained from the diverse areas were less diverse incontent than anticipated. Further, the specific nature of the contentsof the soil were unexpected, and in particular, the particle sizedistribution of the materials in the particulate component of the soilswas unexpected.

In addition, a simulated household dust composition of the presentinvention comprises a fibrous fraction present in an amount of about 45%to about 55% by weight of the composition, and a particulate fractionpresent in an amount of between 45% to 55% by weight of the compositionin which approximately 78% to 100% by weight of the fibrous fraction isformed from cotton fibers, and in which approximately 40% to 70% byweight of the particulate fraction is formed from skin cells. As aresult of additional testing, it has been unexpectedly found that asimulated household dust composition including these fractions andcomponents of the fractions closely mimics household dust compositionsfound in different locations throughout the United States, whichunexpectedly illustrated that very high amounts of both cotton fibersand skin cells were the majority components in these dust compositions.

These, and other aspects of the present invention will be betterappreciated and understood when considered in conjunction with thefollowing description and the accompanying drawings. It should beunderstood, however, that the following description, while indicatingpreferred embodiments of the present invention, is given by way ofillustration and not of limitation. Many changes and modifications maybe made within the scope of the present invention without departing fromthe spirit thereof, and the invention includes all such modifications.

DETAILED DESCRIPTION OF THE INVENTION

The present invention and the various features and advantageous detailsthereof are explained more fully with reference to the non-limitingembodiments described in detail in the following description.

The synthetic testing soil of the present invention was arrived at afterextensive research into what constitutes a typical soil to be found in anormal home environment in the continental United States. Since it wasdesired to establish a soil composition which would be considered to betypical of, or representative of, any region of the country, it wasdetermined that dirt from a variety of locations should be collected andanalyzed to determine the characteristics thereof. Accordingly, sevencities across the United States were selected as geographical centersfor sampling of soil or dirt from uncarpeted areas. A minimum of tenhomes in each city was sampled, using a standardized vacuum cleaningsampling technique. Samples were then returned, and submitted to anindependent contract test laboratory for evaluation of the physicalproperties of the collected dirt. From this data, variability of thephysical compositions of the samples was determined. Further, data wascollected at the sampling sites to indicate variations in theenvironment, such as whether there were pets and/or children in thehousehold. For purposes of the present disclosure, the term “dust” is tobe taken to refer to particulate materials which are airborne, and whichwill fall out of the air to settle on floors, tops of tables, andshelves, etc. Thus, dust is but one part of the artificial test soildeveloped in the present invention.

The test sites for the sampling were chosen to be Phoenix, Miami,Metropolitan New York (Newark), Kansas City, Columbus, Denver, and SanDiego. Twelve homes in each of the cities were prescreened so to eachhave a minimum of 3 rooms which were not carpeted; including a kitchen,a bathroom, and one other room, excluding basements and laundry areas;resident(s) willing to not clean the floors in those rooms for two weeksprior to the sampling; and agreeing to permit representatives of thesampling organization into their homes to collect soil. The householdswere also prescreened and equally distributed between the cities on thebasis of the presence of children under 18, and the presence ofpredominantly indoor cats and dogs. In home visits were conducted untila minimum of 10 homes had been sampled in each city. Study demographicswere also weighted, based upon government statistics from 1990 and 1998,so that homes without pets constituted 40% of the sampling; homes withcats and/or dogs constituted 60% of the sampling; homes with no childrenunder age of 18 constituted 60% of the sampling; homes with childrenunder age of 18 constituted 40% of the sampling; urban area homescomprised 75% of the sampling; and rural area homes comprised 25% of thesampling.

Two samples were taken in each home, one from the kitchen and one fromanother room, resulting in a total of 20 samples from each city. InKansas City, all samples were kept separate, and not pooled. In theremaining 6 cities, the samples were handled as follows: Kitchen samplesfrom 3 homes were kept separate; Other room samples from 3 homes werekept separate; All kitchen samples from the remaining 7 homes werepooled (after weighing individually); All other room samples from theremaining 7 homes were pooled (after weighing individually). A total of68 samples were thus provided for analysis.

Sampling was conducted using Hoover C2024 Port-a-Power commercial vacuumwith hose and standard hard floor cleaning tool. Pre-weighed soilcollection bags were removed from the vacuum cleaner immediately aftersample collection from a given room, sealed, and placed in a Ziploc®,plastic bag for return to the research facility to determine gram/squarefoot collected per sample, and pooling as indicated above. The soilcollection bags were high efficiency vacuum bags obtained from JohnHopkins, made at Midwest Filtration Forms from DuPont Hysurf filtrationmaterial. The material is 95-97% polyethylene thermally bonded, and is98.8% efficient at a 1 micron particle size at a flow rate of 30 cubicfeet per minute.

After sampling, the samples were then forwarded to the independent testlaboratory for analysis. Tests conducted include optical microscopy andvisual exam, with chemical analysis following physical analysis tosubdivide categories and to support weight estimates. Samples werecategorized as comprising: Hair (animal and human); Other fibers(cotton, synthetic, or cellulose); Minerals (clay, quartz, SiO₂, orbuilding materials including gypsum); Exfoliated skin; Food; Plantmaterial (wood, leaves, paper, or insect material). Total analyses ofthe samples were conducted, and from the resulting information, theartificial soil of the present invention was formulated so as tocorrespond closely thereto.

It was found that the typical home dirt generally constitutes threecomponents. Of these components, particulates and hair are critical foreffectively replicating real world home soil. The third component is afiber component which is a preferred but optional component. Tofabricate a suitable artificial test soil, it was necessary to selectspecific readily available and commonly found forms or examples of eachof the materials present in each of the components of the typical homedirt.

The first component of a typical dirt constitutes particulate materials.These particulate materials include a wide range of, mineral materials(such as sand, feldspar, talc, and clay), plant materials (such as driedgrass and dried leaves), and food materials (such as chips or crackers,cereals, starches, proteins, etc.). The particulate component itselfthus falls into three categories or types: mineral, plant, andstarch/food. While it is preferred to have all three categories or typesof particulate represented in the particulate mixture used to make upthe test soil, suitable test soils can be formed from only one or two,of these types of particulate. If all three categories of particulateare present in the test soil, the particulate fraction preferablycomprises 10% to 40% minerals, 20% to 50% food, and 5% to 40% plantmaterial, based upon the particulate weight. The preferred ranges are:20% to 30% minerals, 30% to 40% food debris, and 10% to 30% plantmaterial, based upon particulate weight. If only two components arepresent, the particulate fraction is preferably comprised of likeamounts of the two components.

A typical mineral fraction might include sand of greater than 300microns, sand of less than 75 microns, feldspar of greater than 300microns, feldspar of less than 75 microns, talc and clay. It is alsopossible to include sand and feldspar of a particle size between 75 and300 microns. However, since the food components tend to be largely madeup of particles within this range, it is not always necessary to havethe sand and feldspar present in all three particle size ranges.

The sand used for the artificial test soil is common silica play sandthat has been sieved to produce the appropriate size fractions. Anysimilar sand materials can be used. For the feldspar component, ZemexF-20, available from The Feldspar Corporation, may be used. Othersimilar feldspar materials can also be used. For the talc, commerciallyavailable baby powder was preferred. These products contain talc alongwith some fragrance. For the clay, H. C. Spinks Bandy Black clay may beused. Other similar clay materials can be used.

The second component of the particulate fraction is the plant materialfraction. This fraction can include dried grass and leaves. Typicalplant material can be chopped up grass clippings and chopped up driedleaves. The average length of the grass and leaf material is betweenabout 1 micron and 1 mm. Any type of grass or leaves may be used so longas they are dried and ground to the above size range. Grass clippingsfrom a double bladed mulching power mower made by Honda were used, anddried the grass overnight in an oven at 100° F. The dried grass was thenstored in polyethylene reclosable bags until use. Over time the driedgrass moisture content equilibrated with the ambient level of humidity.The leaves were chopped up to within the same particle range and driedand stored in a similar manner.

The third component of the particulate fraction is the starch/foodfraction. These materials are representative of food crumbs that remainon a floor or counter top. Suitable representative materials include:crushed and sieved Cheerios®, available from General Mills; oats foroatmeal, such as Quaker Oats® old fashioned; crushed saltine crackers;and crushed dried soup mix such as Lipton® Chicken Noodle Cup-a-Soup®mix. The crushed, arid, sieved materials are blended together inappropriate amounts to maintain the desired size distribution. Thestarch/food component tends to have particle sizes in the 75 to 300micron range, and also in the above 300 micron range.

The particulate component should be present in, an amount of from about40% to 80% by weight, preferably in an amount of from about 40% to 70%by weight, and most preferably from about 50% to 65% by weight.

The second required component of the test soil is the hair component.This represents both human and pet hair commonly found in homes. Thehair fraction typically can contain human, cat, and dog hair, in thefollowing relative amounts: 30% to 40% human hair, 30% to 40% cat hair,and 30% to 40% dog hair. There are a wide variety of sources for testhair. Typical human hair is cut in 0.25 to 1 inch lengths. It isimportant that the hairs be fully separated from each other as they areapplied to the test surface. It is also important that the hair strandsbe on the surface as separate strands as much as possible, and not asclumps of hair. To that end, the hair samples are divided apart onapplication as much as possible. It was found that a minimum of tendivisions of the hair sample is adequate, but fifteen divisions or moreis preferred. One reason hair is an important component is that the oilyand electrostatic nature of hair is difficult to replicate with anyother material. Moreover, hair is an important component of householdsoil, showing how the test products react in the presence of hair isdesirable.

The hair component of the soil should be present in an amount of fromabout 20% to 40% by weight, preferably from 20% to 30% by weight andmost preferably from about 20% to 25% by weight.

In addition to the required particulate and hair fractions, it ispreferred that the test soil also have some percentage of a non-hairfibrous material. Typical fibrous materials include cotton fibers, nylonfibers, polyester fibers and other natural and synthetic fiber materialssuch as wool, rayon, acrylics, etc. As a source of cotton, common cottonballs are useful. The cotton is separated to form short strands of fiberthat resemble dust fibers. The typical length is from 5 to 25 mm. Thetypical nylon used is a 3 denier nylon cut into 6.35 mm lengths. Asource of this material is Mini Fibers, Inc. The polyester material usedis also 3 denier and cut to a length of 6.35 mm. The relative ratio ofthese fiber components within the fiber fraction is from 40 to 60% ofnatural fibers and 40 to 60% of synthetic fibers. The preferred rangesare 45% to 55% natural fibers and 45% to 55% of synthetic fibers. It ismost preferred to use a blend of synthetic fibers such as a blend ofnylon and polyester fibers. While it is preferred to use a 50/50 ratioof these fibers, any ratio of these fibers can be used.

If present, the fiber component should be present in an amount up toabout 40%. It is preferred to have the fiber component present in anamount of from about 10% to 30% by weight and most preferably from about20% to 30% by weight.

The test soil can be prepared by combining the two, or preferably three,components shortly before the test is conducted, or these components canbe separately applied to the test surface. It is important that thecomponents not be stored in an amount greater than to be used for asingle test. This is because the components easily separate from eachother and taking a small portion of the test soil from a larger store ofmixture will lead to uneven results. When the components are stored in acombined fashion, they tend to agglomerate, and cannot be sampled andapplied in a reproducible fashion and are of limited use in replicatingreal world household soil.

The test soil may also include certain optional components to reflecteven more accurately real world household soils. Two of these optionalmaterials include pollen, such as ragweed pollen, and human skin cells.Ragweed pollen is available from Air Filter Testing laboratories. Othersimilar pollen materials can be used. The human skin cells used werepowdered human stratum corneum from Prof. Howard Mailbach. Other sourcescan also be used. Other optional materials can be some oils such assebum and the like, which can be absorbed or adsorbed on to the testsoil components. It is important that the oil not completely cover orocclude the particles, however. Also, some moisture can be added. Fortesting of dry soils, minimal added moisture is preferred. It should berecognized that the test soil components can be, and are preferably,stored so that they equilibrate moisture with the ambient conditions.For certain tests of “dried on soil”, the soil can be made up as a pastewith water and then applied to the surface and allowed to dry.

Testing is conducted on a clean test surface. Typical surfaces includeuncarpeted vinyl flooring, ceramic tile flooring, with grout between thetiles, hardwood flooring, laminate countertop material, and the like.The soil is then scattered on the test surface in a random butrelatively uniform fashion. The term “random but relatively uniform”means that there is no particular pattern to the application but thereare also no discernibly larger deposits of material on limited areas ofthe surface. As noted above, the particulate fraction can be appliedfirst, followed by the fiber fraction and then the hair fraction. Thesefractions may be applied in any particular order so long as they areapplied in a random but relatively uniform fashion. With regard to thehair and fiber fractions, as noted above, it is important that these beapplied to minimize the appearance of discernible clumps of hair orfiber on the floor. It is acceptable that there can be some smallagglomeration of these fibers, as this replicates small dust clumps thatcan naturally appear on the surface to be cleaned.

The total amount of soil to be applied depends of the type of testingbeing done. It is important that enough soil be applied so thatsignificant differences can be observed between testing samples. It hasbeen found that amounts of from 0.1 to 10 grams of test soil per squaremeter of surface are suitable and preferred.

The surface is then cleaned by the test implement or composition. Thistest method is suitable for evaluating dust mitts, dusting cloths (bothwoven and non-woven), mops, brooms, vacuums and similar devices. Thecloth materials can be natural or synthetic and may be treated oruntreated with cleaning compositions, including tack materials. Thecloths can also be provided with a material that provides a charge asthe cloth is passed over the surface or the cloth may be pre-charged toprovide an electrostatic charge.

Specific embodiments of the present invention will now be furtherdescribed by the following, non-limiting examples which will serve toillustrate various features of significance. The examples are intendedmerely to facilitate an understanding of ways in which the presentinvention may be practiced and to further enable those of skill in theart to practice the present invention. Accordingly, the examples shouldnot be construed as limiting the scope of the present invention.

EXAMPLES

A test soil, having the composition as set forth in Table 1, wasprepared, and used to test a dusting cloth. Three different testsurfaces were used with a minimum of twenty-five square feet of surfacearea: Seamless vinyl flooring, grouted 12 inch ceramic tile, and oakwood flooring. Each floor was cleaned by the following procedure: thesurface was swept to remove any dirt or particulate, and a 10% isopropylalcohol solution was applied with a trigger spray bottle, and thesurface was cleaned and dried with a non-linting cloth. A 3 foot by 3foot template was placed over the center of the floor material. A 1 gramtotal weight sample of the above test soil was applied to this area bysprinkling the particulate and other optional components over the floorwithin the template, then applying the hair component, being careful toseparate the hair strands from each other using ten divisions of thehair samples, and lastly applying the fiber component in a manner to thehair component. The template was removed, and a pre-weighed dustingcloth was moved over the treated area in a continuous motion, extendingout into the non-treated area, until the entire surface was treated onetime. The pickup on the cloth was measured by weight and compared to theamount put down on the surface. TABLE 1 Soil Composition PercentMATERIAL USED MINERAL COMPONENT Sand >,300 microns 9.620 Silica PlaySand Sand <75 microns 1.200 Silica Play Sand Feldspar >300 microns 9.620Zemex F-20 Feldspar <75 microns 0.925 Zemex F-20 Talc >75 microns 0.462Johnson & Johnson Baby Powder Bandy Black Clay 0.879 H. C. SpinksSubtotal 22.706 STARCH/FOOD MATERIAL Cheerios >300 microns 4.700 Crushedand Sieved Cheerios 75-300 microns 2.300 Crushed and Sieved Quaker Oats3.760 Lipton Cup-a-Soup 4.700 Chicken Noodle, Crushed not SievedCrackers 7.530 Crushed, not Sieved 22.990 PLANT COMPONENT Dried crushedgrass 2.800 Chopped grass clippings Dried crushed leaves 4.200 Dried andchopped Maple Leaves Subtotal 7.000 TOTAL 52.696 PARTICULATES HAIRCOMPONENTS Percent SOURCE Human Hair (0.25-1 inch) 6.750 Demeo Brothers,Virgin Brown Hair Dog Hair 6.750 Biopol Laboratory Cat Hair 6.750 BiopolLaboratory Subtotal 20.250 OPTIONAL FIBER MATERIALS Percent MATERIALUSED Cotton Fibers 12.900 Johnson & Johnson Cotton Ball fiber NylonFibers 6.450 Mini Fibers, Inc., 3 denier, 0.250 inch Polyester Fibers6.450 Mini Fibers, Inc., 3 denier, 0.025 inch Subtotal 25.800 OTHEROPTIONAL MATERIALS Percent SOURCE Ragweed Pollen 0.370 Air FilterTesting Labs Human Skin Cells 0.925 Powdered Human Stratus CorneumSubtotal 1.295 100.000

In this manner, it was possible to compare a number of differing clothsfor effectiveness in removal of the artificial test soil. By comparisonof the percentages of soil picked up by the cloths, accurate assessmentsof the efficacy of cleaning by each of the cloths was possible, with thenumerical ratings confirming visual evaluations made at the time oftesting.

Nonetheless, dust, while being generally similar in composition to soil,does have a different composition than normal household soil. Forexample, dust collects at locations that are normally spaced above theground on which soil collects. Because dust collects in elevatedlocations, as well as on floors, dust is a necessary component of soilas described and defined previously, but due the nature of dust to beairborne, the types and particle sizes of the components of dust aresomewhat different than those of soil in order for the particulate andfibrous materials forming the dust to collect in these elevatedlocations. Previous studies have been conducted to determine thedeposition rate of household dust in elevated locations in order tofigure out the rate of cleaning, or amount of dust that needs to beremoved at specified intervals in order to design cleaning implementscapable of picking up these amounts of dust.

However, these studies, while briefly commenting on the types ofmaterials found in these household dust compositions, did not focus onthe specific types and amounts of the components of these household dustcompositions. Thus, pursuant to a study conducted by the applicant usingsamples of household dust obtained from five geographically distinctU.S. cities, these household dust samples were analyzed to determine thecomponents of each of the household dust samples and the relativeamounts of each of these components within the samples. What wasunexpectedly and surprisingly determined was that the samples containedan inordinate amount of certain specific components, namely, skin celland cotton fiber components, which rendered the dust compositionsignificantly different from a normal soil composition. The reasons forthe disparity in the composition between the household dust sample and asoil sample are not known, but it is assumed that one of the reasons forthe difference in composition is the different sources and sizes of thefibers and particles which make up the respective soil and dustcompositions, namely, the particles that are supplied from outdoor orexterior of the home sources, and sources which are due to everydayliving occurrences happening within the home.

With regard to the dust samples that were obtained and analyzed, anaverage of the samples was taken in order to arrive at the simulated orartificial household dust composition represented below in Table 2:TABLE 2 Dust Components by % Volume Measured Target Measured PropertyVolume % Volume % Fibrous Fraction Cotton Fibers 70-100% 83% SyntheticFibers  10-40%  9% Hair  1-10%  8% Particulate Fraction Skin Cells 40-70% 62% Construction Material and Soil  10-40% 12% Plant Fragments 10-40% 16% Starch  1-10%  4% Low Temperature Combustion  1-10%  1%Cotton  1-10% <1% Sugar   <1% <1% Hair   <1% <1% Rust   <1% <1% Paint  <1% <1% Fungal   <1% <1% Synthetic fibers   <1% <1%

The composition of the simulated household dust includes a fibrousfraction in which the majority component is the cotton fibers, and aparticulate fraction in which the majority component is skin cells. Inaddition, the particulate size of the simulated household dust sample isnecessarily less than that of a soil composition due to the fact thatthe dust composition can be moved by airflows through a home to elevatedlocations on which the dust composition can collect. Thus, in thesimulated dust composition, the particulate size breakdown for thevarious components of the simulated dust composition is represented inTable 3: TABLE 3 Particulate Size Distribution Particulate Size Number %Number % >50 microns  1% 0.4%  10-50 microns 18% 19% 2.5-10 microns 40%37% 0.3-2.5 microns 41% 44%

The particular formulation of the simulated dust composition can takevarious forms. For example, the components for each of the fibrousfraction and particulate fraction other than the cotton fibers and theskin cells may be selected from other suitable materials and constrainedonly by their relative amounts as defined by the percentages disclosedin Table 2. In a preferred embodiment, the dust composition is formedwith a weight fraction of each of the fibrous fraction and theparticulate fraction, as well as the weight fraction of each of thevarious components of each of the fibrous fraction and particulatefraction as illustrated in Table 4. TABLE 4 Dust Component WeightFraction and Preferred Substance Constituting Component Component Wt.Fraction Preferred Component Fibrous Fraction 0.52 Cotton linters 0.4816Cotton linters Synthetic fibers/nylon 0.0061 Claremont FlockCorporation; RC352 semi dull nylon Synthetic fibers/rayon 0.0056Claremont Flock Corporation: NI353 semi dull rayon Hair 0.0264 Cat Hairlot#99-0550RM Biopol Laboratory Inc. (cut to <1 mm length) ParticulateFraction 0.48 Human Skin Cells 0.3225 Obtained by vacuuming employees'bedding/sieved to <53 microns. Contains come small fibers, mostlycotton. Plant Fragments 0.0667 Grass clippings, dried, chopped in acoffee grinder, sieved to <53 microns (USA standard #270). ConstructionDebris 0.0663 USG Sheetrock 210: sieved <53 microns Soil 0.0061 H. C.Spinks Bandy Black Clay (sieved <53 microns) Starch 0.0130 Corn Starch(SCJ SOF 35293) Combustion Particles 0.0056 Cabot Corp.: Black PearlsCarbon BlackIn addition, Table 4 illustrates the preferred substance utilized foreach of the components of both the fibrous fraction and the particulatefraction. However, in addition to this preferred embodiment, otherweight fractions and compositions for the simulated household dustcomposition are contemplated as being in the scope of this invention.More specifically, in order to alter the composition of the simulatedhousehold dust to more closely conform to a dust found in a particularlocation, the weight fractions of the fibrous fraction and particulatefraction, in addition to or separate from the modification of the weightfractions of the various proponents of each of the fibrous fraction andparticulate fraction, can be modified in order to vary the compositionof the simulated household dust composition to conform to the desireddust composition parameters.

To manufacture the test soil, first the components utilized to form thefibrous fraction are selected, weighed or otherwise measured todetermine the proper amount to be used, and added to a first vial orother container to form the fibrous fraction. Next, the components forthe particulate fraction are selected, weighed or otherwise measured todetermine the proper amount to be used, and added to a second vial orother suitable container. Both containers are mixed separately until thevarious fractions contained in the separate containers appear to behomogeneous. The separate fractions are then intermixed with one anotherto form a homogeneous simulated dust composition with the selectedweight and component fractions for the desired simulated dustcomposition.

With regards to industrial applicability, the invention provides animproved standardized soil and dust for testing of cleaning implements,compositions, and methods.

Although the best mode contemplated by the inventors of carrying out thepresent invention is disclosed above, practice of the present inventionis not limited thereto. It will be manifest that various additions,modifications and rearrangements of the features of the presentinvention may be made without deviating from the spirit and scope of theunderlying inventive concept.

Furthermore, all the disclosed features of each disclosed embodiment canbe combined with, or substituted for, the disclosed features of everyother disclosed embodiment except where such features are mutuallyexclusive.

It is intended that the appended claims cover all such additions,modifications and rearrangements. Expedient embodiments of the presentinvention are differentiated by the appended claims.

21. The simulated dust composition for use in evaluating theeffectiveness of cleaning devices, the composition comprising: A) afibrous fraction including cotton fibers present in an amount of betweenabout 70% and about 100% by volume of the fibrous fraction; and B) aparticulate fraction including skin cells present in an amount ofbetween about 40% and about 70% by volume of the particulate fraction.22. The composition of claim 21 wherein the weight ratio of the fibrousfraction to the particulate fraction is between about 1.25:1 and about1:1.25.
 23. The composition of claim 21 wherein the fibrous fraction ispresent in an amount of between about 45% to about 55% by weight of thecomposition, and the particulate fraction is present in an amount ofbetween about 45% to about 55% by weight of the composition.
 24. Thecomposition of claim 21 wherein the fibrous fraction comprises: A)cotton fibers; B) synthetic fibers; and C) hair fibers.
 25. Thecomposition of claim 24 wherein the fibrous fraction comprises: A)cotton fibers are present in an amount of between 70% to about 100% byvolume of the fibrous fraction; B) synthetic rayon fibers are present inan amount of between about 10% to about 40% by volume of the fibrousfraction; C) synthetic nylon fibers are present in an amount of betweenabout 10% to about 40% by volume of the fibrous fraction; and D) hairfibers are present in an amount of between about 1% to about 10% byvolume of the fibrous fraction.
 26. The composition of claim 21 whereina particulate fraction comprises: A) skin cells; B) plant fragments; C)construction material and soil; D) starch; E) low temperature combustionproducts; and F) cotton.
 27. The composition of claim 26 wherein theparticulate fraction comprises: A) skin cells present in an amount ofbetween 40% to about 70% by volume of the particulate fraction; B) plantfragments present in an amount of between 10% to about 40% by volume ofthe particulate fraction; C) construction material and soil present inan amount of between about 10% to about 40% by volume of the particulatefraction; D) starch present in an amount of between 1% to about 10% byvolume of the particulate fraction; E) low temperature combustionproducts present in an amount of between 1% to about 10% by volume ofthe particulate fraction; and F) cotton present in an amount of between1% to about 10% by volume of the particulate fraction.
 28. Thecomposition of claim 21 wherein the composition has a particulate sizedistribution of: A) about 0% to about 1% of particles larger than 15micrometers; B) about 15% to about 20% of particles between about 10micrometers and 50 micrometers; C) about 35% to about 50% of particlesbetween about 2.5 micrometers and about 10 micrometers; and D) about 35%to about 50% of particles between about 0.3 micrometers and about 2.5micrometers.
 29. The composition of claim 21 comprising: A) a fibrousfraction including cotton fibers present in an amount of between about70% to about 100% by volume of the fibrous fraction, synthetic rayonfibers present in the amount of between about 10% to about 40% by volumeof the fibrous fraction, synthetic nylon fibers present in an amount ofbetween 10% to about 40% by volume of the fibrous fraction, and hairfibers present in an amount of between about 1% to about 10% by volumeof the fibrous fraction; and B) a particulate fraction including skincells present in an amount of between about 40% to about 70% by volumeof the particulate fraction, plant fragments present in an amount ofbetween 10% to about 40% by volume of the particulate fraction,construction material and soil in an amount of between 10% to about 40%by volume of the particulate fraction, starch present in an amount ofbetween 1% to about 10% by volume of the particulate fraction, lowtemperature combustion product present in an amount of between 1% toabout 10% by volume of the particulate fraction, and cotton present inan amount of between 1% to about 10% by volume of the particulatefraction.
 30. The composition of claim 21 wherein the composition hasthe following weight fractions for the fibrous fraction and particulatefraction for the individual components of each of the fibrous fractionand particulate fraction: Component Wt. Fraction Fibrous Fraction 0.52Cotton fibers 0.4816 Synthetic fibers/nylon 0.0061 Syntheticfibers/rayon 0.0056 Hair 0.0264 Particulate Fraction 0.48 Human SkinCells 0.3225 Plant Fragments 0.0667 Construction Debris 0.0663 Soil0.0061 Starch 0.0130 Combustion Particles 0.0056


31. A method for forming a simulated household dust composition, themethod comprising the steps of: A) providing a first container and asecond container; B) introducing a number of fibrous fraction componentsinto the first container; C) mixing the fibrous fraction components inthe first container; D) introducing a number of particulate fractioncomponents into the second container; E) mixing the particulate fractioncomponents in the second container; and F) mixing the fibrous fractioncomponents from the first container with the particulate fractioncomponents from the second container.
 32. The method of claim 31 whereinthe fibrous fraction components include cotton fibers present in anamount of between about 70% to about 100% by volume of the fibrousfraction components.
 33. The method of claim 32 wherein the fibrousfraction components include cotton fibers, synthetic fibers, and hairfibers.
 34. The method of claim 33 wherein the cotton fibers are presentin an amount of between about 70% to about 100% by volume of the fibrousfraction components, the synthetic fibers are present in an amount ofbetween about 10% to about 40% by volume of the fibrous fractioncomponents, and the hair fibers are present in an amount between about1% to about 10% by volume of the fibrous fraction components.
 35. Themethod of claim 31 wherein the particulate fibrous components includeskin cells present in an amount of between about 40% to about 70% byvolume of the particulate fraction components.
 36. The method of claim35 wherein the particulate fraction components include skin cells, plantfragments, construction material, soil, starch, low temperaturecombustion products, and cotton.
 37. The method of claim 36 wherein theskin cells are in an amount between about 40% to about 70% by volume ofthe particulate fraction components, the plant fragments are present inan amount of between about 10% to about 40% by volume of the particulatefraction components, the construction material and soil are present inan amount of between 10% to about 40% by volume of the particulatefraction components, the start is present in an amount between about 1%to about 10% by volume of the particulate fraction components, the lowtemperature combustion products are present in an amount of betweenabout 1% to about 10% by volume of the particulate fraction components,and the cotton is present in the amount of between about 1% to about 10%by volume of the particulate fraction components.
 38. The method ofclaim 31 wherein the step of mixing the fibrous fraction componentscomprises mixing the fibrous fraction components until homogeneouslymixed in the first container.
 39. The method of claim 31 wherein thestep of mixing the particulate fraction components comprises mixing theparticulate fraction components until homogeneously mixed in the secondcontainer.
 40. The method of claim 31 wherein the step of mixing thefibrous fraction with the particulate fraction comprises mixing thefibrous fraction and particulate fraction until homogeneously mixed.